The present invention relates to a process for modernizing an open-end spinning machine, which comprises a plurality of adjacently arranged spinning aggregates, each of which consists essentially of an opening unit for opening a sliver fed to the spinning aggregate into single fibers, and of a rotor unit comprising a spinning rotor, the opening unit and rotor unit each comprising a plurality of components.
It is known from U.S. Pat. No. 4,150,462 that spinning machines are modernized by exchanging whole drafting units. Here, a plurality of new drafting units are affixed adjacent to one another to a joint longitudinal section. After the old drafting units of the spinning machine have been disassembled, a longitudinal section containing the new drafting units is assembled on the spinning machine undergoing modernization. The aim of these measures is to prevent assembly errors during modernization of the spinning machine.
The ideas disclosed in the above mentioned publication are only suitable to a certain extent for the modernization of the openend spinning machine. They are not suitable, for example, when a single spinning aggregate is to be disassembled.
It is an object of the present invention to demonstrate a method for modernizing an open-end spinning machine in which the efficiency of the open-end spinning machine is improved.
This object has been achieved in accordance with the present invention in that one of the components is replaced by at least one modernized component in such a way that the efficiency of the spinning aggregate is improved. Improved efficiency leads to better economic viability of the open-end spinning machine operational speeds.
As the amount of yarn which can be produced by an open-end spinning machine is proportional to the number of revolutions of the spinning rotor, an increase in the possible operational speed results directly in an increase in productivity and thus to improved efficiency.
It is hereby advantageous to assemble a modified radial bearing for the spinning rotor in such a way that the effective length of the rotor shaft between two bearing points of the radial bearing is shortened, or that the length of the rotor shaft projecting out over a bearing point is shortened. The length of the rotor shaft between the two bearing points can be shortened in that the radial bearing itself is modified. The length of the rotor shaft projecting out over a bearing point can for example be shortened in that the relative distance between the above mentioned bearing point and an axial bearing adjacent thereto is reduced. It has been shown that the critical speed of the spinning rotor is greatly dependent on the intermediate space, located between two bearing points, and spanned over by the rotor shaft, and on the length of the section piece of the rotor shaft projecting over the last bearing point. The shortened construction of the modified bearing unit means that the rotor shaft can be shortened. The critical speed of the spinning rotor can be increased without the diameter of the rotor shaft having to be enlarged.
In an advantageous embodiment, the pressure with which the drive belt is pressed against the rotor shaft can be regulated. The power consumption can hereby be reduced in that the pressure can be regulated to the relevant required minimum, thus improving the economic efficiency of the open-end spinning machine. The power saved can be applied elsewhere, for example for increasing the operational speed.